Planoqkaph co



E. FrG. GIBBS.

REVERSIBLE BORING BAR HOLDER,

APPLICATION FILED 061115. l9l5.

Patented July 1, 1919.

Snow View 651M4 4 411,4, 6

2 SHEETS-SHEET l.

THE COLUMBIA PLANOORAPH co.. WASNINDTON. n. c.

E. PM. GIBBS. REVERSIBLE BQHING BAR HOLDER. APPLICATION FILED 00 1. 15. I9I5.

- 1,308,282. 1111611111 July 1, 1919.

2 SHEETS-SHEET 2.

UNITED STATES PATENT OFFICE.

EDWARD rues. GIBBS, or wasmnsr ofn, nrsrrtioror COLUMBIA.

Z10 all whom it may concern:

a citizen ofthe United States, residing at Washington, in the District of Columbia,

have invented certain new and useful Improvements in Reversible Boring-Bar Hold ers, of which the following is a specification. I f

My invention relates to that class of boring bar holders which, the toolpost being removed, are bolted directly tothe tool seat of an ordinary engine lathe, andhold the bars, which, in turn, hold the insertedcuu ing apertures, and which is adapted to lathes ratio by reversing the block fboth longitudinally and vertically, (end for end and upside down); the complete mechanism of.

which is illustrated in the accompanying drawings, which fornr a part of this speci fication, and in which drawings l I Figure 1 is aplanviewof; he holdercomplete, holding a boring? bar with cutter in working position. I Fig, 2 is aside elevation'showinga sectionof the boring ;bar. l 3

Fig. .3 is a central sectional view on line w w of Fig. 1.,

Fig.,4 isan end view. $1,; I

Fig. 5 is a plan view of an-elevating liner. Fig. 6 is a side elevation of the saidliner.

Reference now being had to the detailsof the drawings by letter, in which similar letters refer to similarparts throughout the several views--- W 3 A designates theyholder .proper or block,

a the bar-holding apertures, a? the main opening or hollow of the bl0ck,a the set Be it known that I, EDWARD GIBBS,

nnvnnsnstn nonme-nennornnn.

Specification Metat rsa PatenijdJ -1y 1,1919 Application filedocto'ber 15,1915. Serial No. 56,000.

I screw lugs, a the numerical characters which I express the respectlveelevations in inches,

while a ldesignates the female centers which indicate the horizontal center lines of the apertures. l 1 I B designates the kingbolt by which the holder "isbolted to the tool ring seat. I I C desi ates the bar-pressing set screws by which the bar is clamped in working posi- 't1on.I I

Ddesignates the boring bar. Edesignates the inserted cutter.

F designates the elevating liner. Block A, being a metallic casting, I eliminatethe original cost of a large amount of superfluous I metal, lighten the holder, facilitate manufacture and obtain a mechanical advantage by internal coring.

FromFigs. 1, 2 and 3 it is seen that a horizontally elongated, bar-holding (cored) aperture a whose apex isyturnedtoward the king bolt 13, passes transversely through each endof the block atright angles to its sides,

Iand-wparallelnto its" top and bottom surfaces and to eachother. I l I 1 The said apertures, a, are connected by another-:(cored) opening,.the main hollow of the box a which, constricted 'atboth ends, extends through the entire length of the block and through the apertures as shown in Figs. 1,2,3, and 4. I I I I I Figs. 1, 2 and 3 show that the box or block A, being cored out between its walls, the in-- flserted ban E, pressed by set screws, 0, bears against the two side walls only; thus advantageously separating thebearing points to the greatest extent I I I Itis further shown that set screws C, havingscrew thread engagement in lugs, a enterthe apertures and. force the inserted bar back toward, and very near theking bolt, B. This and thecloseproximity of theiapertures tothe king bolt is designed to bring the strain receiving point of cutter, D, as near-directly in front of the king bolt as possible forthe sake of rigidity.

Also .Ithe bar-holding apertures, a, are elongated horizontally rather than vertically. in

;.order that the centers of bars of various sizes will fall in the same horizontal plane.

HIt is understood thataiboring bar in op- I eration should mamtam an elevation 1n which its axial center moves inIthe same horizontall jplanej as thatuoftheaxial center of the lathespindle or a little lower. 1,

Using theactual working drawing dimen-.

cast on the topof the block over the bar;

the block now being reversed Vertically, (upside down) the elevation of the bar is 1 3 inches, which fact is indicated by the proper character on the surface of the block above the bar and when it is again reversed, longitudinally, the fourth elevation of the bar is 1%}; inches and the .fact indicated by the proper character on the block above the bar. Thus when the elevation of the lathe center is known the holder can be intelligently set,

or the characters-may be integral numbers and refer to certaln lathes of that number.

However, a series of four elevations, in-

creasing at the ratio of one-eighth of an inch each is thus obtained in a practical onepiece holder, which will accommodate most of the lathes in general use, but not all. The range of elevations, in my opinion, should cover about one inch, for a universal holder. Nor is it practical to increase the ratio of increase from one-eighth to one quarter of an mch, nor is 1t practlcal to rest the holder on four surfaces instead of two in reversing it, nor is it desirable to use elevating liners at all, espe'ciallythin ones, because they must be detached, and thin liners impair rigidity. I adopt,'therefore a halfinch liner, whose thickness inch) added to the lowest elevation of the block (1% inches) is equal to its highest elevatibn (1% inches) plus the ratio of increase Q inch). In other words, its thickness is such as to maintain the ratio of increase.

g It is to be seen that the minimum and maximum elevations are vertical opposites and that the sum of their elevations is equal to the sum of'the two intermediate elevations; thus it is that the so-called top and bottom surfacelines shown in Figs. 2 and 3 are parallel. j

Female centers, a shown'in Figs. 1 and 2,

denote-the horizontal centerlin'es of the apertures, a and are used in connection with the tail stock center of the lathe.

In cases Where only one or two elevations are required I e'flect economy, both in manufacture andmetal by using a hollow block with only one bar holding aperture, which reverses vertically only.

Rigidity maybe increased in both cases by employing tv'v'o king bolts, one located near each vertical wall. This ceuld not be properly done if the last described block was solid and had set screws entering the aperture from the rear end.

Having thus fully described my invention, I submit the following claims:

1. A. reversible boring bar holder, comprising a block having two similar, horizontal, vertically opposite, bearing surfaces, one

set screws enter the said aperture; all sulistantially as set forth.

2. A reversible boring bar holder, COlllprising a hollow block having two similar, horizontal, vertically opposite, bearing surfaces adapted to bear on the tool seat of an engine lathe having a transverse, horizontal, bar holding aperture through one end, unequally distanced between the said horizontal bearing surfaces, and connected with the main hollow of the block, between its side walls; and having also means for clamping the said block to the tool seat of an engine lathe; and means for clamping a boring bar in the said aperture; all substantially as set forth.

3'. A reversible boring bar holder, comprising a hollow block having two similar, horizontal, vertically opposite, bearing surfaces adapted to bear on the tool seat of an engine lathe; having a transverse, horizontal, horizontally elongated, bar holding aperture through its end, whose apex is turned toward the king bolt, unequally distanced between the said horizontal bearing surfaces, and connected with the main hollow of'the block between its side walls; and having also horizontally disposed lugs through which bar pressing set screws enter the said aperture; and means for clamping the said block to the tool seat of an engine lathe; all substantially as 'set'forth.

4:. A reversible boring bar holder, comprising a hollowblock having two similar, horizontal, vertically opposite, bearing surfaces adapted to bearon the tool seat of an engine lathe; having a transverse, horizontal bar holding aperture through each end, each aperture being unequally distanced between the said horizontal bearing surfaces, connected with each other through the main hollow of the block; and entered by bar pressing set screws; and a vertical king bolt passing through the said horizontal bearing surfaces; all substantially as set forth.

5. A reversible boring bar holder, comprising a block having two similar, horizontal, vertically opposite bearing surfaces adapted to bear on the tool seat of an engine lathe; having a transverse, horizontal, bar holding aperture through each end, each aperture being unequally distanced between the said horizontal bearing surfaces, and differing with each other in elevation to an extent equal to the difference between the two intermediate elevations of the block; means for clamping boring bars in the said apertures; and a vertical kingbolt passing through the said bearing surfaces; all sub stantially as set forth.

6. A universal boring bar holder, comprising a reversible bloc-k having two similar, horizontal, vertically opposite, bearing surfaces adapted to bear on thetool seat of an engine lathe; having a transverse, horizontal, bar holding aperture through each end, the said apertures differing with each other in elevations to an extent equal to the diiference between the two intermediate elevations of the block; in combination with an elevating liner whose thickness added to 7. A reversible boring bar holder, c0m

prising a block having two similar, horizontal, vertically opposite bearing surfaces adapted to bear on the tool seat of an engine lathe; having a transverse bar-holding aperture through each end; unequally distanced between the top and bottom surfaces, the minimum and maximum elevations being vertically opposite to each other; and means for clamping the said block to the tool seat of an engine lathe; all substantially as set forth.

In testimony whereof I aliix my signature in presence of two Witnesses.

EDWARD F-G. GIBBS. Witnesses:

A. L, HOUGH, A. R. FOWLER.

Copies of this patent may be obtained for five cents eaeh,by addressing the Commissioner of Patents,

Washington, D. G. 

